Palletizer with box layer preparation

Abstract

The invention relates to a palletizer including a device ( 24 ) for preparing and prestacking layers of boxes, said device consisting of: a vertically moveable table ( 25 ); two tables ( 26, 26 ′) forming a noria and capable of alternately taking the place of said table ( 25 ) and of depositing another layer of boxes onto the layer standing by on said table ( 25 ); a means for calibrating each layer of boxes according to the palletization scheme. The table ( 25 ) and the table ( 26, 26 ′) are used to perform the operation of calibrating the layers of boxes by moving said boxes against an abutment ( 40 ) which, in an inoperative position, acts as a slider bed between the table ( 25 ) and the palletization table ( 7 ). The table ( 26, 26 ′) consists of rollers ( 30 ) which are mounted on one-way bearings.

1 .- 9 . (canceled) 
     
     
         10 . A Palletizer comprising, on a same general chassis:
 a preparation zone for preparing layers of boxes, which preparation zone comprises:   a first conveyor for conveying boxes,   a group or row-preparation station for preparing groups or rows of boxes,   a layer-preparation station for preparing each layer of boxes,   a palletization zone for an actual palletization which comprises a palletization station and a deposit table,   pushers for moving said boxes and layer(s) of boxes from said preparation zone towards said palletization zone and,   a second conveyor which conveys empty pallets to said palletization station, the palletizer further comprising, at said layer-preparation station:   a main table which is vertically moveable from a high position for preparing a first layer of boxes to a low position standing by for another layer of boxes, which main table is constituted by a motorized endless belt, which is used for setting the boxes in motion and pressing the boxes against a retractable transverse abutment, in order to calibrate said layer of boxes, in a longitudinal direction of circulation of said boxes on said main table,   lateral cleats cooperating with said retractable transverse abutment for calibrating said layer of boxes at said layer-preparation station,   at least two interim tables each capable of taking the place of said main table when said main table is in said low position with at least one layer of boxes, which interim tables are horizontally moveable, guided between an operative position of occupation of a window left free by said main table, in order to receive groups or rows of boxes and allow a new layer of boxes to be formed, and an inoperative position which said interim tables reach by being retracted and separated from said new layer of boxes, which is deposited on said layer of boxes present on said main table by gravity alone, as an interim table which is in operation is retracted,   said pushers comprising a first pusher which moves groups or rows of boxes between said group- or row-preparation station and said layer-preparation station, and   a second pusher which moves the layer or layers of boxes between said layer-preparation station and said palletization station.   
     
     
         11 . The palletizer according to  claim 10 , further comprising at said layer-preparation station, two identical interim tables which are each constituted by a flexible panel produced with rollers with a small diameter mounted on a free wheel, which interim tables are mounted opposite each other, on endless chains and the assembly of said interim tables and endless chains forms a noria, which endless chains are arranged laterally, on each side of said layer-preparation station, guided in a frame borne by said general chassis which extends around said main table, and a free space between said two interim tables corresponds at least to a length of a receiving surface area of said main table in order to allow said main table to pass through when said main table is placed in said operative position for receiving rows of boxes, which endless chains are moved sequentially forwards in a direction which corresponds to a direction of advance of said layers of boxes towards said palletization station. 
     
     
         12 . The palletizer according to  claim 11 , wherein said rollers of each said interim table, are mounted on bearings comprising a free wheel so as to set said boxes in motion and press said boxes against said transverse abutment in order to automatically calibrate a layer of boxes according to a palletization scheme, as said rollers are retracted during the depositing of said layer of boxes on said layer of boxes which is situated on said main table. 
     
     
         13 . The palletizer according to  claim 10 , further comprising means for calibrating each layer of boxes according to a palletization scheme, which means for calibrating are constituted, on the one hand, by a retractable abutment which is arranged transversally with respect to a direction of travel of said boxes on said layer preparation station for preparing and stacking the layers of boxes, at the downstream end of said layer-preparation station and, on the other hand, by cleats arranged laterally on each side of said layer-preparation station. 
     
     
         14 . The palletizer according to  claim 13 , wherein said transverse abutment is arranged and positioned so that, in said inoperative position, said transverse abutment acts as a slider bed joining said main table and said deposit table of said palletization zone. 
     
     
         15 . The palletizer according to  claim 10 , wherein said main table comprises a support which is borne by a cradle, which cradle extends transversally beyond noria frames of said noria, and said cradle is guided vertically on posts which form part of said general chassis on which said noria frames are fixed, and said cradle is maneuvered in the vertical direction by means of a mechanism integrated into said posts of said chassis, which mechanism is constituted by further chains firmly fixed to said cradle, which further chains are arranged in said side posts and are driven by a common servomotor. 
     
     
         16 . A method for prestacking several layers of boxes in order to delay an operation of palletizing said several layers on a palletizer constituted, on a same general chassis by:
 a preparation zone for preparing layers of boxes, which preparation zone comprises:   a first conveyor for conveying boxes,   a group or row-preparation station for preparing groups or rows of boxes,   a layer-preparation station for preparing each layer of boxes,   a palletization zone for an actual palletization which comprises a palletization station and a deposit table,   pushers for moving said boxes and layer(s) of boxes from said preparation zone towards said palletization zone and,   a second conveyor which conveys empty pallets to said palletization station, the palletizer further comprising, at said layer-preparation station:   a main table which is vertically moveable from a high position for preparing a first layer of boxes to a low position standing by for another layer of boxes, which main table is constituted by a motorized endless belt, which is used for setting the boxes in motion and pressing the boxes against a retractable transverse abutment, in order to calibrate said layer of boxes, in a longitudinal direction of circulation of said boxes on said main table,   lateral cleats cooperating with said retractable transverse abutment for calibrating said layer of boxes at said layer-preparation station,   at least two interim tables each capable of taking the place of said main table when said main table is in said low position with at least one layer of boxes, which interim tables are horizontally moveable, guided between an operative position of occupation of a window left free by said main table, in order to receive groups or rows of boxes and allow a new layer of boxes to be formed, and an inoperative position which said interim tables reach by being retracted and separated from said new layer of boxes, which is deposited on said layer of boxes present on said main table by gravity alone, as an interim table which is in operation is retracted,   said pushers comprising a first pusher which moves groups or rows of boxes between said group- or row-preparation station and said layer-preparation station, and   a second pusher which moves the layer or layers of boxes between said layer-preparation station and said palletization station,   the method comprising:   preparing a layer of boxes on said main table from a previously formed group of boxes;   calibrating said layer of boxes according to a palletization scheme and putting said layer of boxes into the format of a receiving pallet, on said main table;   vertically retracting said main table, by a height substantially greater than the thickness of said layer of boxes;   installing an interim table in the space left free by said main table;   conveying a new group of boxes onto said interim table and calibrating said new group of boxes in the same way as said layer of boxes and vertical to said layer of boxes;   retracting said interim table keeping a corresponding new layer of boxes framed in order to deposit said new layer of boxes directly on said layer of boxes which is arranged on said main table, at a lower level;   once there is no longer any need for delay, returning said main table to the level of said deposit table, with different superimposed layers of boxes surimposed on said main table; and,   transferring said superimposed layers of boxes to said palletization station in order to deposit them on said pallet.   
     
     
         17 . The method for prestacking several layers of boxes, according to  claim 16 , wherein comprising simultaneously carrying out a transfer of said superimposed layers of boxes towards said palletization station and a setting up of new rows of boxes on said main table for formation of an initial layer of boxes. 
     
     
         18 . The method for prestacking several layers of boxes, according to  claim 17 , wherein in order to carry out said calibration of each layer of boxes, the method comprising:
 stopping boxes on said transverse abutment situated at a downstream end of said layer-preparation station in order to longitudinally press said boxes by means of said main table or one of said interim tables,   transversally pressing boxes constituting each layer, by means of lateral cleats bordering said layer-preparation station, which cleats are moveable above said main or interim table which bears said corresponding layer and,   longitudinally pressing said boxes by means of said corresponding main or interim table, under the effect of the adherence between the different boxes and said corresponding main or interim table, by a longitudinal movement of said corresponding main or interim table in a direction from a preparation table of said group or row-preparation station for preparing the rows of boxes towards said palletization station.